package com.prj.ufdm.auth.config;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.security.access.SecurityMetadataSource;
import org.springframework.security.access.intercept.AbstractSecurityInterceptor;
import org.springframework.security.access.intercept.InterceptorStatusToken;
import org.springframework.security.web.FilterInvocation;
import org.springframework.security.web.access.intercept.FilterInvocationSecurityMetadataSource;
import org.springframework.stereotype.Service;
import com.prj.ufdm.auth.security.UrlDecisionManagerImpl;
import com.prj.ufdm.auth.security.UrlMetaDataSourceImpl;

/**  
 * Spring Security 权限控制（授权）
 * @author 胡义振  
 * @date 2018年3月24日  
*/
@Service
@AutoConfigureAfter(UrlMetaDataSourceImpl.class)
public class AuthUrlInterceptor extends AbstractSecurityInterceptor implements Filter {
	
	@Autowired
	@Qualifier("urlMetaDataSourceImpl")
	private FilterInvocationSecurityMetadataSource urlMetaDataSourceImpl;

	/**
	 * 交给 AccessDecisionManager 处理是否放行
	 * @param urlDecisionManagerImpl
	 * @author 胡义振  
	 * @date 2018年3月24日
	 */
	@Autowired
	public void setUrlAccessDecisionManager(UrlDecisionManagerImpl urlDecisionManagerImpl) {
		super.setAccessDecisionManager(urlDecisionManagerImpl);
	}
	
	/**
	 * 授权过滤器
	 * FilterInvocation fi 里面有一个被拦截的url
	 * 里面调用UrlMetadataSource的getAttributes(Object object)这个方法获取fi对应的所有权限
	 * 再调用UrlAccessDecisionManager的decide方法来校验用户的权限是否足够
	 * @param urlDecisionManagerImpl
	 * @author 胡义振  
	 * @date 2018年3月24日
	 */
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		FilterInvocation fi = new FilterInvocation(request, response, chain);
		InterceptorStatusToken token = super.beforeInvocation(fi);
		try {
			// 执行下一个拦截器
			fi.getChain().doFilter(fi.getRequest(), fi.getResponse());
		} finally {
			super.afterInvocation(token, null);
		}
	}
	
	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		
	}

	@Override
	public void destroy() {
		
	}

	@Override
	public Class<?> getSecureObjectClass() {
		return FilterInvocation.class;
	}

	@Override
	public SecurityMetadataSource obtainSecurityMetadataSource() {
		return this.urlMetaDataSourceImpl;
	}

}
